---
title: "How to allow hydrology parameter overrides to a river network"
slug: "how-to-allow-hydrology-parameter-overrides-to-a-river-network-at-simulation-runtime"
description: "Read about how to allow hydrology parameter overrides to a river network at simulation runtime. "
tags: ["1D river modelling", "hydrology", "rainfall-runoff", "ReFH", "FSR", "boundary conditions"]
updated: 2022-08-02T13:05:14Z
published: 2022-08-02T13:05:14Z
canonical: "help.floodmodeller.com/how-to-allow-hydrology-parameter-overrides-to-a-river-network-at-simulation-runtime"
stale: true
---

> ## Documentation Index
> Fetch the complete documentation index at: https://help.floodmodeller.com/llms.txt
> Use this file to discover all available pages before exploring further.

# How to allow hydrology parameter overrides to a  river network at simulation runtime

The inflow parameters for a simulation can be adjusted - select an alternative return period in hydrological boundaries, scale Flow-Time series data, and more! Alternatively, inflow data can be provided via a specifically formatted .csv file, and this can also store multiple flow profiles for selection within your simulation.

In both cases, no adjustments are needed to the underlying network - the boundary nodes will allow parameter overrides by default.

![1DRiverimagesparameteroverride.PNG](https://cdn.document360.io/5074bc26-a9ef-4bf4-b1de-a5c6ce628aca/Images/Documentation/1DRiverimagesparameteroverride.PNG)

When setting up a [River Simulation](/v1/docs/1d-river-simulation-window), you can specify parameters to be overridden in boundaries that have this box checked. Please note checking this box (alone) within the boundary nodes themselves will not adjust anything - the overrides must be also specified within the simulation itself.

For **FSSR**, **FEH**, **ReFH** and **ReFH2** boundaries, the return period and storm duration can be specified for the simulation, to override those provided within the boundary nodes themselves. Additionally, all inflow boundaries (the 4 mentioned above, together with the **Flow-Time**, **Rainfall-Evaporation**, and **Generic Rainfall-Runoff** boundary) can have scaling factors specified, to apply to the rainfall and total flow provided within the boundary nodes. These parameter override values are all defined when [Configuring the Hydrology tab](/v1/docs/how-to-configure-the-hydrology-tab).

An additional option is to override the flow-time series altogether. Inflow data can be provided in .csv format and can be specified to override the total flow provided within the boundary nodes themselves. The .csv data, and which boundary nodes are overridden, are all defined when [Using Flow-Time Series Data](/v1/docs/how-to-use-flow-time-series-datafiles).

## Related topics

More about [River Boundary Nodes](/v1/docs/river-boundaries-overview)